1. Field of the Invention
The present invention relates to a thickness adjustment device for thin-film coating, especially to a thickness adjustment device for thin-film coating that coats materials to form uniform thin films and controls the thickness of the coated films.
2. Descriptions of Related Art
Along with the development of modern technology, a plurality of electronic products have been invented and introduced in the market. Most of these electronics include components produced by coating methods. A single or a composite coating material is coated on a substrate or a surface of the substrate. In conventional coating technologies, the surface of the substrate is coated with a selected coating material by manually operated brush coating or scrape coating. Thus the coating is uneven, the coated film is with different thickness, or a part of the surface is uncoated. In some application fields which require higher coating quality or use special coating materials, manual operation is not feasible so that coating mechanisms are used to increase production efficiency.
A conventional coating mechanism used in film industry, tape industry, printed circuit board (PCB) industry is roller coating. In roller coating, a roller of an upper film and a roller of a lower film respectively are in rolling contact with a coating roller. The coating roller is fixed or is pressed by roller shafts on two sides for film coating. However, during coating and film lamination of the coating roller, the film produced is thick and uneven. Thus the coating quality is poor, the defective rate is high, and the manufacturing cost is increased.
For example, while manufacturing fuel cells, catalyst materials are coated on surfaces of carbon substrate. The power conversion efficiency of the fuel cell will be adversely affected if the coating is not even. Moreover, if users want to adjust the thickness of the film to be coated, the distance between rollers needs to be adjusted. For getting different film thickness, rollers are adjusted frequently. This causes inconvenience for film coating.
During the manufacturing process of liquid crystal display, a surface of liquid crystal display is coated with a protective film for preventing scratches caused by abrasion or impacts. Before attaching the protective film to the surface of the liquid crystal display, an adhesive film is coated on the surface of the liquid crystal display to facilitate attachment of the protective film. If the adhesive film is not coated evenly, the protective film is unable to be attached closely, giving rise to distortions or wrinkles easily. The manual coating tends to lead to uneven coating and varying thickness of the adhesive film. Some parts of the surface are even uncoated. Without close attachment, the protective film is easy to peel or come off.
In addition, the thickness of the film coated by conventional coating mechanisms is at the millimeter (mm) scale or micron-meter (μm) scale. The thickness of the coated film is unable to be controlled in the nanometer scale.
Thus there is a room for improvement and a need to provide a thickness adjustment device for thin-film coating that coats materials on work pieces evenly and controls the thickness of the coated films. The thickness of the coated films is controlled at the nanometer (nm) scale so as to solve the above problems.